Manually adjustable ruggedized focus mechanism

ABSTRACT

The invention provides, in some aspects, devices for image acquisition that use seals (e.g., O-rings) between concentrically disposed portions of an enclosure and an optics assembly (or sub-assemblies thereof) in order to protect image acquisition components from the surrounding environment (and vice versa) while, at the same time, providing adequate friction for both adjusting and locking focus. Such devices include, in one aspect of the invention, an image capture medium (e.g., a CMOS sensor, CCD array, etc.) that is disposed within an enclosure and an optics assembly that is also disposed within that enclosure, rotatably. The optics assembly, which includes at least a lens, can have a cylindrical outer diameter along at least a portion of its length that is received within the enclosure along a length that has a corresponding cylindrical inner diameter. A first seal (e.g., an “O-ring”) is disposed between, and in contact with, the optics assembly and the enclosure, e.g., along these corresponding lengths. That seal permits rotation of the optics assembly for purposes of focusing the lens, while preventing (or reducing a risk of) contamination from the environment (e.g., water, chemicals, dirt, dust, etc.) from entering into the enclosure and vice versa.

BACKGROUND OF THE INVENTION

The invention pertains to image acquisition and, more particularly, toimage acquisition devices that can be manually adjusted and that aresealed to the elements, e.g., water, chemicals, dirt, dust.

Image acquisition refers to the capture of still or video images. Itforms a basis for “machine vision,” i.e., the computer processing ofimages, and is used in manufacturing and industry for robotic assembly,parts inspection, quality control, etc. It is also increasingly used inmilitary and security, as well as commercial and residential,applications.

Image acquisition devices, or “cameras” as they are commonly called,optimally utilize adjustable focus lenses. These have an advantage overfixed-focus lenses in that they permit optics (e.g., lens “glass”) to beset at optimal focal points for objects at varying distances, thusinsuring sharpness of both close (or far) objects.

In traditional industrial and manufacturing image acquisitionapplications, cameras are used indoors (e.g., on factory floors) incontrolled environments. As the range of image acquisition applicationsbroadens, there is increasing need for cameras that can be used outdoorsor in other less controlled situations, e.g., where there is dust, dirt,water, chemicals, and so forth.

To this end, ruggedized cameras are often protected from the environmentby a protective cover and/or an enclosure. However, in order for anoperator (e.g., plant worker, military/security personnel, home owner,etc.) to focus the cameras, the protective covers must be removed. Notonly is this inconvenient, but it runs the risk of exposing the lens topotentially harmful factors. Moreover, such adjustment often requiresthe use of particular tools, which can be expensive and complicated touse.

Image acquisition devices with adjustable focus lenses routinely usemotorized focus mechanisms and/or external locking features. Thedrawbacks of the former are that the motorized mechanisms are morecomplicated, expensive, and prone to failure, e.g., due to power loss,breakage, and so on. The drawbacks of the latter are that if an operatorfails to set or release a lock, focussing may be substantially impaired.Moreover, setting and releasing the locks adds an additional step tooperations.

An object of the invention is to provide improved image acquisitiondevices and methods.

A further object of the invention is provide such devices and methods asoperate in rugged environments without exposing the lens.

A still further object of the invention is to provide such devices andmethods as provide for focusing of the lens, e.g., without motorizedmechanisms and/or the use of tools.

A still further object of the invention provide such devices and methodsfor locking of focus positions with improved focal accuracy and speed.

A still yet further objects of the invention provide such devices andmethods as can be produced at low cost.

SUMMARY OF THE INVENTION

The foregoing are among the objects attained by the invention whichprovides, in some aspects, devices for image acquisition that use seals(e.g., O-rings) between concentrically disposed portions of an enclosureand an optics assembly (or sub-assemblies thereof) in order to protectimage acquisition components from the surrounding environment (and viceversa) while, at the same time, providing adequate friction for bothadjusting and locking focus.

Such devices include, in one aspect of the invention, an image capturemedium (e.g., a CMOS sensor, CCD array, etc.) that is disposed within anenclosure and an optics assembly that is also disposed within thatenclosure, rotatably. The optics assembly, which includes at least alens, can have a cylindrical outer diameter along at least a portion ofits length that is received within the enclosure along a length that hasa corresponding cylindrical inner diameter. A first seal (e.g., an“O-ring”) is disposed between, and in contact with, the optics assemblyand the enclosure, e.g., along these corresponding lengths. That sealpermits rotation (or direct translation, e.g., by pushing or pulling) ofthe optics assembly for purposes of focusing the lens, while preventing(or reducing a risk of) contamination from the environment (e.g., water,chemicals, dirt, dust, etc.) from entering into the enclosure and viceversa.

In a related aspect of the invention, the first seal permits at leasttemporary fixation of the optics assembly relative to the enclosure—and,thereby, at least temporary fixation of focus—as a result of a frictionfit effected between it, the assembly and the enclosure.

In another aspect, the invention provides a device for image acquisitionas described above in which the optics assembly includes a lenssub-assembly and a window sub-assembly. The lens sub-assembly includesthe lens, while the window sub-assembly includes an opticallytransparent cover (e.g., a window) and, for example, a focusing ring.The cover/window protects the lens and other image acquisitioncomponents that are within the enclosure from the environment, whilepermitting passage of light (or other rays) comprising images to becaptured. The focusing ring facilitates grasping the window sub-assembly(and, more generally, the optics assembly) for purposes of rotating theassembly relative to the enclosure and/or rotating the windowsub-assembly relative to the lens sub-assembly—and thereby facilitatesfocusing the lens, e.g., on the CMOS, CCD or other capture medium.

In still other aspects of the invention, the lens sub-assembly isdisposed within the window sub-assembly. In this regard, the lenssub-assembly can have a cylindrical outer diameter along at least aportion of its length that is received within the window sub-assemblyalong a length that has a corresponding cylindrical inner diameter. Asecond seal (again, for example, an “O-ring”) is disposed between, andin contact with, the respective sub-assemblies, e.g., along thesecorresponding lengths. That seal prevents (or reduces a risk that) anycontamination that might have entered the enclosure, e.g., in a region“behind” the optics assembly, from entering the optics assembly, e.g.,in the region between the lens (or lens sub-subassembly) and the window(or window sub-assembly). This can be useful, for example, in preventingany water, dust, etc., that may have entered the enclosure from cloudingthe lens or window).

As a result of a friction fit, that seal also permits at least partialcoupling of the lens and window sub-assemblies, e.g., so that rotationof the focus ring (particularly) and/or the window sub-assembly(generally) translates to the lens sub-assembly and, thereby,facilitates focusing the lens. Because that rotational friction can beovercome, at least in some aspects of the invention, the seal canprevent excess rotation of the focus ring (particularly) and/or thewindow sub-assembly (generally) from being translated to the lens and,thereby, for example, from stripping lens-mount threading.

In another aspect, the invention provides a device for image acquisitionas described above in which the lens sub-assembly is coupled to theenclosure (or otherwise) such that rotation of that sub-assembly variesthe distance between the lens and the CCD (or other image capturemedium)—and, thereby, focuses images received by the lens on the CCD (orother image capture medium).

In related aspects of the invention, that coupling is provided viacorresponding threading on the lens sub-assembly (or lens itself) and amount in the enclosure. That threading can include sealing materials,such as silicone, rubber, etc. to prevent any contamination that mighthave entered the enclosure from reaching the lens and/or the CCD or(image capture medium).

In still further aspects of the invention, as the distance between thelens and the CCD (or other image capture medium) varies, e.g., onaccount of rotation of the focus ring (particularly) and/or the windowsub-assembly (generally), one or both of the O-rings (or other seals)permits linear translation of (a) the optics assembly (and windowssub-assembly) relative to the enclosure and/or (b) the windowsub-assembly relative to the lens sub-assembly.

In yet another aspect, the invention provides methods of focusing, e.g.,a device for image acquisition as described above, by rotating theoptics assembly in order to vary the distance between the lens and theCCD (or other image capture medium). In related aspects, the inventionprovides such methods in which such rotation is effected by rotating thefocus ring (particularly) and/or the window sub-assembly (generally)and, thereby, rotating the lens sub-assembly, so as to linearly androtationally translate the lens (or lens sub-assembly) along a threadrun provided by a mount that is coupled to the enclosure. In furtherrelated aspects of the invention, first and second seals as discussedabove provide selective rotational coupling of the sub-assemblies, whilepermitting one or both of them to translate linearly for focusing.

These and other aspects of the invention are evident in the drawings andin the detailed description that follows.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the invention may be attained byreference to the drawings, in which:

FIG. 1 depicts an image acquisition device according to one practice ofthe invention. The device includes an enclosure, which protects devicecomponents (e.g., a lens) from the surrounding environment, having arotatable window sub-assembly that facilitates focusing of the lenscomponent;

FIG. 2 depicts an exploded image acquisition device having a lensassembly, a window sub-assembly, and an enclosure, according to onepractice of the invention; and

FIG. 3 depicts the exploded image acquisition device of FIG. 2 fromanother viewpoint, showing the internal structure of the windowsub-assembly and enclosure.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT

FIG. 1 depicts an image acquisition device 10 according to one practiceof the invention. The device 10 includes a enclosure 12 having an opticsassembly 11 rotatably disposed therein. The enclosure 12 housescomponents of the image acquisition device (e.g., a lens 32, an imagecapture medium, etc., as discussed below), protecting them from dust,dirt, water, moisture, and/or other elements of the surroundingenvironment (or more broadly, preventing an exchange or transfer ofunwanted elements between the enclosure 12 and the environment). In theillustrated embodiment, enclosure 12, which may be “ruggedized,”comprises ceramic, metal, plastic and/or other materials suitable forproviding such protection under the device's 10 expected operatingconditions.

FIG. 2 is an exploded view of the enclosure 12 and the optics assembly11. The illustrated optics assembly 11 comprises a lens sub-assembly 24that is coupled to a window sub-assembly 14 as discussed below. Thewindow sub-assembly 14 is, in turn, rotatably coupled to the enclosure12, also as shown. It has a cylindrical outer diameter along at least aportion 15 a of its length that is received within the enclosure 12along a length 15 b that has a corresponding cylindrical inner diameter,all as shown. More generally, in the illustrated embodiment, the opticsassembly 11 and the portion of the enclosure 12 in which it is receivedare generally of circular cross-section; though, in other embodimentsthey may be shaped otherwise consistent with the teachings hereof.

The window sub-assembly 14 includes an optically transparent cover 16, afocusing ring 18, and a first seal 34, all as shown. The cover or“window” 16 protects the lens 32 (as well, more generally, as thesub-assembly 24) and other image acquisition components (e.g., chargecoupled device (CCD) or other capture medium) that are within theenclosure 12 from the environment, while at the same time permittingpassage of light or other rays (e.g., infrared, X-ray, and so forth)intended for capture by the CCD (or other image capture medium). In theillustrated embodiment, cover 16 is comprised of plastic, glass, orother materials suitable to meet the above requirements in expectedoperating conditions. In some embodiments of the invention, the cover 16itself comprises a lens, e.g., for providing additional (or the solemeans of) focusing for the device 10.

The focusing ring 18 facilitates grasping the window sub-assembly 14(and, more generally, the optics assembly 11) for purposes of rotatingthe assembly 11 relative to the enclosure 12 and/or rotating the windowsub-assembly 14 relative to the lens sub-assembly 24, therebyfacilitating focusing of an image, e.g., on the CCD or other capturemedium. In the illustrated embodiment, the focusing ring 18 is knurled,though, in other embodiments, it may be textured otherwise.

With continued reference to FIG. 2, the first seal 34 seals sub-assembly14 (and the optics assembly 11 generally) within enclosure 12 (e.g., byan interference fit, friction fit, or otherwise). The sealing functionminimizes the risk of contaminants from the environment (e.g., water,chemicals, dirt, dust, etc.) entering into the enclosure 12, e.g., intoa region 17 a “behind” the optics assembly 11 and, thereby, adverselyaffecting operation of the lens 32, CCD, or other component of device10. Similarly, the seal 34 also prevents any desirable gases, fluids,etc., from escaping the enclosure 12 in to the environment.

The seal 34 also concurrently permits rotation (e.g., via the focusingring 18) of the window sub-assembly 14 for purposes of (a) focusing thelens 32, and (b) facilitating at least a temporary fixation of theoptics assembly 11 relative to the enclosure 12, and, thereby, at leasttemporary fixation of a focus, e.g., as a result of a friction fiteffected between it, the assembly 11 and the enclosure 12. Compared toprior art systems, this has the added benefit of providing increasedfocal accuracy by removing the possibility that an operator may fail toset and/or release separate fixing (e.g., locking) features. Moreover,the seal 34 reduces focus time by eliminating the requirement of settingand/or releasing separate fixing (e.g., locking) features of the typeprovided in prior at systems.

In the illustrated embodiment, the first seal 34 is disposed between thewindow sub-assembly 14 (and thus, the optics assembly 11) and enclosure12, along an outer diameter 36 (or “barrel”) of the sub-assembly 14,e.g., in the region denoted 15 a. In the illustrated embodiment, theseal 34 comprises, e.g., an elastomeric O-ring. In other embodiments, itmay be a different type of seal suitable for protectively sealing theoptics assembly 11 to the enclosure 12, and fixing a lens focusposition, under expected operating conditions.

Returning to FIG. 2, the lens sub-assembly 24 of the illustratedembodiment is generally cylindrically shaped—albeit, here, with portions25-27 of varying outer diameter. The assembly 24 comprises a second seal28, and threads 30. It also comprises at least one lens 32, configuredas shown.

Lens 32 is of the conventional type used in the art to gather light orother rays comprising an image (e.g., still, video, or otherwise) forprojection onto the capture medium. In the illustrated embodiment, lens32 is an optical lens, e.g., an M12 lens, though in other embodiments itmay be sized otherwise or configured for collecting other wavelengths.

The image capture medium (not shown) captures an image focused onto itby lens 32. In the illustrated embodiment, the device 10 comprises oneor more charge-coupled device (CCD) arrays, CMOS sensors, film, magnetictape, or other medium suitable for capturing an image through the lens32. The medium is disposed within a “back” portion of enclosure 12,though, in other embodiments it may be disposed elsewhere.

The second seal 28 facilitates protectively affixing (e.g., sealing) thelens sub-assembly 24 to the window sub-assembly 14, and at leasttemporarily fixing the lens 32, lens sub-assembly 24, and/or windowsub-assembly 14, in one or more focus positions. The seal 28 prevents(or reduces a risk that) any contamination that might enter theenclosure 12, e.g., in a region “behind” the optics assembly, fromentering the optics assembly 11, e.g., in the region between the lens 32(or lens sub-assembly 24) and the window 18 (or window sub-assembly 14).This can be useful, for example, in preventing any water, dust, etc.,that may have entered the enclosure 12 from clouding the lens 32 orwindow 18.

In the illustrated embodiment, such sealing and fixing of a focus isachieved by the seal 28 facilitating a fit (e.g., friction fit,interference fit, or otherwise) of the lens 32/lens sub-assembly 24 andthe window sub-assembly 14, and/or a fit of the lens 32/lenssub-assembly 24 and the enclosure 12. As a result of the fit, that seal28 facilitates at least partial coupling of the lens 32 andsub-assemblies 14, 24, e.g., so that rotation of the focus ring 18(particularly) and/or the window sub-assembly 14 (generally) translatesto the lens sub-assembly 24 and, thereby, facilitates focusing of thelens 32. Because that rotational friction can be overcome, the seal 28also prevents excess rotation of the focus ring 18 (particularly) and/orthe window sub-assembly 14 (generally) from being translated to the lens32 and, thereby, for example, from stripping lens-mount threading 30,40, discussed below. In the illustrated embodiment, the second seal 28is an O-ring comprised of, e.g., plastic, rubber, or otherwise, disposedalong diameter 25, as shown, though in other embodiments it may bedisposed elsewhere in a manner suitable for providing protective sealingunder expected operating conditions.

With continued reference to FIG. 2 and the lens sub-assembly 24, threads30 engage opposing threads on a lens mount 38 (discussed below) torotatably couple the lens sub-assembly 24 to the enclosure 12, therebyfacilitating focusing of the lens 32. In the illustrated embodiment,threads 30 form a run on an outside surface of diameter 27, though, inother embodiments they may be disposed elsewhere (e.g., diameter 25,diameter 26, etc.). The threads 30 can further include sealingmaterials, such as silicone, rubber, etc., to prevent any contaminationthat might have entered the enclosure 12 from reaching the lens 32and/or the CCD or (image capture medium).

The aforementioned lens sub-assembly 24 couples with the lens mount 38in order to facilitate focusing of the lens 32. In the illustratedembodiment, the mount 38 is of a cylindrical shape, of the same materialas the enclosure 12, of a size sufficient to hold the lens sub-assembly24, and disposed on an inside surface of enclosure 12, as shown.Moreover, the mount 38 is sized to permit a full range of lens 32adjustments (e.g., in view of thread 30 length) for the range ofexpected focal lengths with which the device 10 is expected to be used.Coupling of the lens mount 38 and lens sub-assembly 24 is achieved asthreads 30, disposed on an outside diameter of lens sub-assembly 24,engage opposing threads 40 on an inside diameter of the lens mount 38.In other embodiments, mount 38 may be of a different material, size,and/or shape, suitable for coupling with the lens sub-assembly 24 underexpected operating conditions. Moreover, other embodiments may include alens sub-assembly 24 that is disposed on an outside diameter of mount38, and/or coupling may be achieved by a means different from threading.

FIG. 3 depicts an exploded view of image acquisition device 10, showingan internal structure of the enclosure 12 and window sub-assembly 14. Inthe illustrated embodiment, the enclosure 12 has a rear portion, asshown, that houses the image capture medium (not shown) and othercircuitry (not shown), though, in other embodiments they may be housedelsewhere.

The window sub-assembly 14 comprises an internal structure as shown,including a mount 50. The mount 50 couples with the lens sub-assembly 24to facilitate affixing the lens sub-assembly 24 to the windowsub-assembly 14. In the illustrated embodiment, the seal 28 forms a fit(e.g., an interference fit, or otherwise) with an inner diameter ofmount 50, though, in other embodiments it may be affixed otherwise. Themount 50 is of a sufficient size and shape (e.g., cylindrical) as tohold the lens mount 24 within an inner diameter of the mount 50, and isdisposed on an inside surface of the window sub-assembly 14, as shown.Moreover, the mount 50 is sized to permit a full range of lens 32adjustments (e.g., in view of thread 30 length) for the range ofexpected focal lengths with which the device is expected to be used.

In operation, device 10 is placed into an environment (e.g., submergedunderwater) for capturing images of that environment (and objectstherein). An operator may focus an image on the image capture medium bymanually rotating the focus ring 18 (particularly) and/or the windowsub-assembly 14 (generally), which varies the distance between the lens32 and the CCD (or other image capture medium), thereby, rotating thelens sub-assembly 24, so as to linearly and rotationally translate thelens 32 (or lens sub-assembly 24) along the thread run 40 provided bythe mount 38 that is coupled to the enclosure 12. In further relatedaspects of the invention, first and second seals 34, 28 as discussedabove provide selective rotational coupling of the sub-assemblies 14,24, while permitting one or both of them to translate linearly forfocusing.

Described above are devices and methods meeting the aforementionedobjects, among others. Those skilled in the art will appreciate that theembodiments discussed and shown herein are merely examples of theinvention and that other embodiments fall within the scope thereof.Thus, by way of non-limiting example, it will be appreciated thatmultiple O-rings (or other seals) may be used in place of, or inaddition to, the rings shown in FIGS. 2-3 and discussed above. It willalso be appreciated by way of non-limiting example, that such sealingmay be provided integrally with the window sub-assembly, the lenssub-assembly, or enclosure, e.g., through overmolding or othermanufacturing/assembly techniques. By way of still further example, itwill be appreciated that, in further embodiments, focusing can beachieved other than by rotating the window sub-assembly. For example, itmay be achieved by directly linearly translating that sub-assemblyrelative to the enclosure and/or lens sub-assembly (e.g., by pushing orpulling—rather than, or in addition to, rotating). In view thereof, whatwe claim is:

1. An image acquisition device for use in an environment, comprising A. an enclosure, B. an image capture medium disposed within the enclosure, C. an optics assembly that is rotatably disposed within the enclosure and that includes a lens, and D. a first seal that is in contact with at least the optics assembly, the first seal permitting rotation of the optics assembly in order to effect focusing of an image received by the lens on on the image capture medium while, at the same time, preventing contamination of at least selected components of the environment into the enclosure or vice versa.
 2. The device of claim 1, wherein the first seal permits at least temporary fixation of the lens and/or the optics assembly in one or more focus positions.
 3. The device of claim 2, wherein the first seal provides such temporary fixation via a friction fit.
 4. The device of claim 1, wherein the optics assembly has a cylindrical outer diameter along at least a portion of its length that is received within the enclosure along a length that has a corresponding cylindrical inner diameter.
 5. The device of claim 4, wherein the first seal is disposed between, and in contact with, the optics assembly and the enclosure along at least a portion of the aforesaid lengths.
 6. The device of claim 4, wherein the first seal permits rotation of the optics assembly for purposes of focusing the lens, while reducing a risk of one or more of (i) contamination from the environment from entering into the enclosure, and (ii) contamination from the enclosure from entering into the environment.
 7. The device of claim 6, wherein the first seal is an O-ring.
 8. The device of claim 6, wherein the first seal is integral with the optics assembly.
 9. The device of claim 1, wherein the optics assembly comprises a lens sub-assembly and a window sub-assembly.
 10. The device of claim 9, wherein the lens sub-assembly comprises the lens.
 11. The device of claim 9, wherein the window sub-assembly includes an optically transparent cover.
 12. The device of claim 11, wherein the optically transparent cover comprises a lens.
 13. The device of claim 11 wherein the optically transparent cover permits any of optical or other rays intended for capture by the image capture medium to pass to the lens.
 14. The device of claim 9, wherein the lens sub-assembly is rotatably disposed within the window sub-assembly.
 15. The device of claim 14, wherein the lens sub-assembly has a cylindrical outer diameter along at least a portion of its length that is received within the window sub-assembly along a length that has a corresponding cylindrical inner diameter.
 16. The device of claim 15, comprising a second seal that is disposed between, and in contact with, the window sub-assembly and the lens sub-assembly along at least a portion of the aforesaid lengths thereof.
 17. The device of claim 16, wherein the second seal comprises an O-ring.
 18. The device of claim 16, wherein the second seal is integral with the lens sub-assembly.
 19. The device of claim 16, wherein the second seal reduces a risk of contamination from the enclosure into the optics assembly.
 20. The device of claim 16, wherein the second seal permits at least partial rotational coupling of the lens sub-assembly and the window sub-assembly.
 21. The device of claim 20, wherein the second seal permits at least partial rotational coupling of the lens sub-assembly and the window sub-assembly so that rotation of the window sub-assembly translates to the lens sub-assembly and, thereby, facilitates focusing the lens.
 22. The device of claim 21, wherein that coupling is effected by a friction fit.
 23. The device of claim 9, wherein the lens sub-assembly is coupled to the enclosure such that rotation of that sub-assembly varies the distance between the lens and the image capture medium.
 24. The device of claim 23, wherein the coupling between the lens sub-assembly and the enclosure is effected by threading.
 25. The device of claim 24, comprising stops that prevent excess travel of the lens sub-assembly.
 26. An image acquisition device for use in an environment, comprising A. an enclosure, B. an image capture medium disposed within the enclosure, C. a window sub-assembly that includes an optically transparent cover and that is rotatably disposed within the enclosure, D. a lens sub-assembly that includes a lens and that is disposed within the window sub-assembly, E. a first seal that is in contact with at least the window sub-assembly, the first seal permitting rotation of the window sub-assembly relative to the enclosure while, at the same time, preventing contamination of at least selected components of the environment into the enclosure, F. a second seal that is disposed between, and in contact with, the window sub-assembly and the lens sub-assembly along at least a portion of the aforesaid lengths thereof, G. the lens sub-assembly being coupled to the enclosure such that rotation of that sub-assembly varies the distance between the lens and the image capture medium.
 27. The device of claim 26, wherein the image capture medium comprises any of a CMOS sensor, charge-coupled device (CCD).
 28. The device of claim 26, wherein the window sub-assembly has a cylindrical outer diameter along at least a portion of its length that is received within the enclosure along a length that has a corresponding cylindrical inner diameter.
 29. The device of claim 26, wherein the lens sub-assembly has a cylindrical outer diameter along at least a portion of its length that is received within the window sub-assembly along a length that has a corresponding cylindrical inner diameter.
 30. A method of focusing an image acquisition device of claim 1, comprising rotating the optics assembly in order to vary the between the lens and the image capture medium.
 31. A method of focusing an image acquisition device of claim 26, comprising rotating the window sub-assembly in order to vary the between the lens and the image capture medium.
 32. An image acquisition device for use in an environment, comprising A. an enclosure, B. an image capture medium disposed within the enclosure, C. an optics assembly that is disposed within the enclosure and that includes a lens, and D. a first seal that is in contact with at least the optics assembly, the first seal permitting translation of the optics assembly in order to effect focusing of an image received by the lens on on the image capture medium while, at the same time, preventing contamination of at least selected components of the environment into the enclosure or vice versa. 